Firearms that use gun powder such as rifles and artillery equipment need to have their barrels cleaned out after firing due to the accumulation of soot, dirt and other residues. Common cleaning agents for the removal of such sooty residues include lubricating oil, diesel fuel and engine oil. These substances can be corrosive and toxic to the human body, and need to be handled with care. Contact with the skin causes absorption into the body, and prolonged contact with the skin also causes wrinkling.
The use of animal bones for various purposes is well known. In one method, animal and fish bones are fried in used cooking coil for a short time. The treated bones are burnt to ashes and particles, and then used as pigments, fertilisers and polishing aids. These bone remains can also be used as additives in fine porcelain, filtering agent and deodoriser. The remaining cooking oil is normally used to manufacture low quality soap and wax.